[X] My Assistant

[tedstryk]

Other than the Iapetus encounter, I noticed that flybys of Mimas (108,000 km), Enceladus (189,000 km), and Rhea (153,500km) are mentioned. Is anything planned for these flybys? I would normally just assume no, given their proximity to the Huygens mission (they are all on the 16th). But considering the Ta and Tc information sheets didn't mention the Tethys non-targeted flyby on Ta, I am surprised that they are mentioned at all. Given this, is any imaging planned?

Ted

[volcanopele]

The one I know for sure about is Rhea, where we should get a good view of its giant ray crater (rays are giant, the crater itself maybe fairly small)

[tedstryk]

Great to hear. Will this include any of the wispy terrain?

[Bjorn Jonsson]

The one I know for sure about is Rhea, where we should get a good view of its giant ray crater (rays are giant, the crater itself maybe fairly small)

Do you know the approximate latitude and longitude of that crater ? I don't see it in Voyager-derived maps of Rhea (or maybe it's not obvious there), yet most of the areas in view in mid-January were rather well imaged by Voyager 1.

[Decepticon]

The one I know for sure about is Rhea, where we should get a good view of its giant ray crater (rays are giant, the crater itself maybe fairly small)

Do you know the approximate latitude and longitude of that crater ? I don't see it in Voyager-derived maps of Rhea (or maybe it's not obvious there), yet most of the areas in view in mid-January were rather well imaged by Voyager 1.

Top Left bottom image Bjorn. http://astrogeology.usgs.gov/Projects/Satu...s/rhea_full.jpg



And link to site where this map was found.
http://astrogeology.usgs.gov/Projects/SaturnSatellites/

[Decepticon]

Another great link with the orginal voyager image with that crater.

http://planetary.org/saturn/rhea.html

[volcanopele]

Wasn 't sure if it was in the Voyager images, nor do I remember the lat and lon of the ray crater. I was just told that the images taken in January will show that ray crater.

[Bjorn Jonsson]

I managed to figure this out myself. North seems to be roughly up in this image:

http://ciclops.lpl.arizona.edu/view.php?id=506

Assuming this I made the attached preliminary cylindrical map by adding the Cassini data to areas of lower resolution Voyager coverage. I only very crudely corrected for varying illumination. The big crater at upper left is visible in exactly the same location (but at lower resolution) in the Voyager based map so this map seems to be correct. Longitude 0 is at the center of the map. The next step is to render this thing to see what Cassini will image...

Attached thumbnail(s)

 

[Decepticon]

^Amazing!

Have you had time to do the same to dione using the recent images?

[Decepticon]

Interesting...

Spacecraft time (UTC) Ground time (UTC) Event
Jan 16
06:08  Jan 16
07:15  Cassini flies by Mimas
The flyby will be at a distance of 108,000 kilometers (67,000 miles) and a speed of 1.3 kilometers per second (2,900 miles per hour). This is just a little bit closer than Voyager 1 ever got.
06:16 07:23 Cassini flies by Enceladus
The flyby will be at a distance of 189,000 kilometers (117,000 miles) and a speed of 10.2 kilometers per second (22,800 miles per hour). Voyager 2 got 50% closer than that, but with the difference in quality between Cassini''s and Voyager's cameras, the Cassini images will be more informative.
06:26 07:33 Saturn Periapsis
At a distance of 4.8 Saturn radii from the planet (or 290,000 kilometers, or about 180,000 miles), this is just outside the orbit of Enceladus. 
11:58 13:05 Descending ring plane crossing
At a distance of 5.9 Saturn radii from the planet (or 360,000 kilometers, or about 220,000 miles), this is outside Enceladus' orbit, inside the E ring. Particles in the E ring are too small to be hazardous to Cassini.
15:51 16:58 Cassini flies by Rhea
The flyby will be at a distance of 153,500 kilometers (95,400 miles) and a speed of 5.1 kilometers per second (11,400 miles per hour). Voyager 1 got two times closer than that, but with the difference in quality between Cassini''s and Voyager's cameras, the Cassini images will be more informative.

From here bottom of page... http://www.planetary.org/news/2005/huygens...eline_0110.html

[tedstryk]

I hope this means they are doing imaging.

06:16 07:23 Cassini flies by Enceladus
The flyby will be at a distance of 189,000 kilometers (117,000 miles) and a speed of 10.2 kilometers per second (22,800 miles per hour). Voyager 2 got 50% closer than that, but with the difference in quality between Cassini''s and Voyager's cameras, the Cassini images will be more informative.

Not to mention that at Voyager's closest approach the scan platform was stuck and it didn't do any imaging at all!

I have noticed that there have been no raw images since those taken January 1. Is this due to the Titan encounter. I know it was going to stop at some point, but I didn't think it was that far out.

[volcanopele]

I hope this means they are doing imaging.

06:16 07:23 Cassini flies by Enceladus
The flyby will be at a distance of 189,000 kilometers (117,000 miles) and a speed of 10.2 kilometers per second (22,800 miles per hour). Voyager 2 got 50% closer than that, but with the difference in quality between Cassini''s and Voyager's cameras, the Cassini images will be more informative.

Not to mention that at Voyager's closest approach the scan platform was stuck and it didn't do any imaging at all!

I have noticed that there have been no raw images since those taken January 1.  Is this due to the Titan encounter.  I know it was going to stop at some point, but I didn't think it was that far out.

I just took a look at the imaging plans for Tc, and yes, Mimas, Enceladus, and Rhea observations are planned to compliment the Iapetus, Tethys, Dione, and Phoebe coverage we have already.

[pioneer]

Mimas, Enceladus, and Rhea observations are planned to compliment the Iapetus, Tethys, Dione, and Phoebe coverage we have already.

Phoebe? What observations can we get from such a large distance we didn't get from the June flyby?

[volcanopele]

Mimas, Enceladus, and Rhea observations are planned to compliment the Iapetus, Tethys, Dione, and Phoebe coverage we have already.

Phoebe? What observations can we get from such a large distance we didn't get from the June flyby?

I meant that we already have regional scale (and in the case of Phoebe, local scale) coverage of Dione, Phoebe, Iapetus, and Tethys, and coverage in Tc will give us Enceladus, Mimas, and Rhea.

Looking at the Enceladus coverage, looks like it will be a gap fill in the leading hemisphere. Not as good as Voyager's best coverage, but it is much better than what we have of that region.

[tedstryk]

Why has no imagery from Jan 1 to Jan 6 when they turned the instruments off been posted?

Ted

[volcanopele]

Why has no imagery from Jan 1 to Jan 6 when they turned the instruments off been posted?

Ted

Because no images were taken.

[tedstryk]

Good answer

[Decepticon]

In order to serve a larger audience, we are temporarily disabling the raw image search function to allow a greater number of people to access press releases and materials related to the Huygens probe descent.

This service will return next week.

WHAT!

Great No raw images for week.

[DEChengst]

WHAT!

Great No raw images for week.

That means we can't create any mosaics from the fly-bys on Sunday.

[Decepticon]

Exactly!

[tedstryk]

Does next week mean Sunday or a week from today?

[Bjorn Jonsson]

Hopefully next week means next Monday (January 17). Actually I'm not surprised of this, yesterday it was almost impossible to access the Cassini website for several hours.

Meanwhile, here are some appetizers. First Mimas as it should appear near closest approach. The only problem is that I don't know when it will be imaged.

[djellison]

WHAT!

Great No raw images for week.

That means we can't create any mosaics from the fly-bys on Sunday.

Well - you CAN - just not right now.

Doug

[DEChengst]

Well - you CAN - just not right now.

I'm too lazy to wait that long

[Bjorn Jonsson]

And here's Enceladus. As before, I do not know when it will be imaged, hardly near closest approach though since it occurs at a very high phase angle. The view near midnight looks nice though.

Note that the field of view in these renderings is 0.175 so Enceladus' relative size is two times what it will be in the actual images.

[tedstryk]

Have you done a rendering of Rhea for this orbit?

[Bjorn Jonsson]

And finally, here's Rhea. These look a bit ugly since I used a preliminary map I did that contains data from a low-res Cassini image but I didn't remove the seams.

The bright rayed crater discussed earlier in this thread isn't visible until several hours after closest approach (i.e. not until the following midnight) so I assume Rhea will be imaged at at least two different times.

The field of view is 0.7 degrees, i.e. two times the FOV of Cassini's narrow angle camera.

Next project: An animation of the February Enceladus flyby.

[Decepticon]

Went threw my bookmarks and I made a point of bookmarking latest 500 images just in case. (Last Week )

Keep an eye out for some pics since the Hyper Link was disabled on the Cassinni Page.

http://saturn1.jpl.nasa.gov/multimedia/ima...?browseLatest=1

[tedstryk]

Cool! Thanks. I thought they had really taken the raws down.

Ted

[volcanopele]

ISS imaging of Mimas, Rhea, and Enceladus is now on the ground.

[volcanopele]

You guys will love this view of Herschel

[tedstryk]

Jason, do you know if the "raw images" section files are updated by a person or it is an automated process?

[volcanopele]

Jason, do you know if the "raw images" section files are updated by a person or it is an automated process?

I believe it is an automated process, but sometimes it breaks.

[alan]

New image of Mimas
http://saturn1.jpl.nasa.gov/multimedia/ima...7/N00026509.jpg

look here if raw image link is still not available at cassini homepage
http://saturn1.jpl.nasa.gov/multimedia/ima...?browseLatest=1

Thanks Decepticon for putting the link up

[alan]

Wow check out the groves on Enceladus
http://saturn1.jpl.nasa.gov/multimedia/ima...7/N00026570.jpg

[alan]

Another of Mimas
http://saturn1.jpl.nasa.gov/multimedia/ima...7/N00026551.jpg

[alan]

Check out the frosted craters on Rhea
http://saturn1.jpl.nasa.gov/multimedia/ima...7/N00026548.jpg

[alan]

Enceladus again
http://saturn1.jpl.nasa.gov/multimedia/ima...7/N00026534.jpg

[alan]

Enceladus with one crater all by itself
http://saturn1.jpl.nasa.gov/multimedia/ima...7/N00026481.jpg

[OWW]

I think it's safe to say we can write off the idea of Europa being 'the smoothest moon in the solar system' in all the textbooks.

( yeah yeah, I know, the other hemisphere of Enceladus has craters... )

[volcanopele]

I'm making color composites now for these...

[Bjorn Jonsson]

Wow, this hemisphere of Enceladus looks much more interesting than the 'Voyager 2 hemisphere' which will be visible during the close flyby next month. Almost no craters are visible and those that can be seen are small.

Fortunately this hemisphere should be nicely covered during the targeted flyby in March.

[djellison]

To be honest - using RGB - there's little to be gained from a single b'n'w image

Slightly more on Enc using cl1-ir1 / p120-grn / p120-UV3





Cranking the levels a LOT with that - on the bottom image - you can see some sort of linear feature between two different types of surface very clearly - I dont think this is an imaging artifact - has this been seen before?

Doug

[Decepticon]

New image of Mimas
http://saturn1.jpl.nasa.gov/multimedia/ima...7/N00026509.jpg

look here if raw image link is still not available at cassini homepage
http://saturn1.jpl.nasa.gov/multimedia/ima...?browseLatest=1

Thanks Decepticon for putting the link up

I knew it would come in Handy one day.

[Decepticon]

Enceladus will join my Most Favorite moon 2nd to Europa.

This moon may be going threw the same process as Europa.
I was hoping to see some Ice Volcanos!

[tedstryk]

Maybe you will in February. If they exist, they may not be huge, or they may release flood "lavas" rather than plumes. Jason, do you know if VIMS took any data this orbit?

Here is my color attempt for Tc Rhea. After producing RGB color, I merged it with the clear filter image to use for grey, to mitigate the effects of spacecraft motion.

Attached thumbnail(s)

 

[volcanopele]

Maybe you will in February. If they exist, they may not be huge, or they may release flood "lavas" rather than plumes. Jason, do you know if VIMS took any data this orbit?

Here is my color attempt for Tc Rhea. After producing RGB color, I merged it with the clear filter image to use for grey, to mitigate the effects of spacecraft motion.

Some of our Mimas and Enceladus observations were VIMS and UVIS ridealongs so I assume they took data as well.

For those doing color composites, I suggest IR3-GRN-UV3 for the Icy satellites. It seems to bring out some color.

[volcanopele]

Slightly more on Enc using cl1-ir1 / p120-grn / p120-UV3


Cranking the levels a LOT with that - on the bottom image - you can see some sort of linear feature between two different types of surface very clearly - I dont think this is an imaging artifact - has this been seen before?

Doug

where did you get the images for the bottom frame?

[volcanopele]

More Rhea images to come. The images on the ground so far have a resolution ~3 km/pixel. There are 5 sets of observations left, with the next set having a resolution of 860 m/pixel.

[djellison]

They're identical to the top image - just stretching the brightness 'down' in photoshop



The more you take it down - the more obvious the deliniation between the two possible areas becomes.

Doug

[tedstryk]

I look forward to it. Jason, I will have to try your filter suggetion, I just used R G B2 plus a clear image.
Unfortunately, my time for image processing is going to be less. Tomorrow I begin classes. I am teaching seven classes this semester (yes, they really need to hire someone new but there is no money for that so we are all teaching overloads). So I should be quite busy. I have Friday totally off though, which is nice.

[volcanopele]

The next set of images should be down shortly.

[Guest_Sunspot_*]

Latest batch of pictures have been posted.

http://saturn1.jpl.nasa.gov/multimedia/ima...&storedQ=860260

Link on the Cassini site is still down though.

[tedstryk]

Wow, these are incredible!

Can't wait for next month's Enceladus flyby. Looks like some sort of canyon on the termniator.

Well, off to class!

Attached thumbnail(s)

 

[tedstryk]

A crescent Rhea.

Attached thumbnail(s)

 

[OWW]

Another (rough) mosaic of Rhea:

Attached thumbnail(s)

 

[Decepticon]

Both are great! ^^

[Guest_paulanderson_*]

In the newest images of Rhea, there is an interesting long linear feature (as with the ones on Dione and Iapetus):

http://dazza101.blogspot.com/2005/01/rhea-...ted-detail.html

Larger version:

http://photos1.blogger.com/img/112/2250/10...6544_50_reg.jpg

There are seven raw full-disk images which show the linear feature here:

http://saturn.jpl.nasa.gov/multimedia/imag...&storedQ=879709

Some are better than others, but it is in all of them, the last one in sequence probably the sharpest (N00026544.jpg). I wish there were some closer shots. As far as I can tell, none of the closer shots that are posted so far have this particular feature in view.

Whether this is a ridge as on Iapetus or a groove as on Dione I'm not quite sure. If not an imaging artifact, then we have yet another similar oddity. What is it with these icy Saturnian moons and such features?

[Guest_paulanderson_*]

CICLOPS now has it's own enhanced version of this view of Rhea (the trailing hemisphere it turns out), with the linear feature clearly seen, but no commentary on it:

http://ciclops.lpl.arizona.edu/view.php?id=739

Also a good TPS update here:

http://www.planetary.org/news/2005/cassini...ladus_0201.html

Thoughts, anyone?

[Decepticon]

TPS has a Icy small moons update!

I find it funny that the cassinni site does not have this info.

http://www.planetary.org/saturn/cassini_tour.html

[alan]

March 12 2008 encounter with Enceladus altitude = 100 km

[Decepticon]

Great Updates of Icy moons Maps!

Love this webpage.

http://laps.fsl.noaa.gov/albers/sos/sos.html

[Decepticon]

http://saturn1.jpl.nasa.gov/multimedia/ima...fm?imageID=1343

[Guest_Sunspot_*]

Can't wait for a closeup look at Enceladus

[alan]

http://saturn.jpl.nasa.gov/multimedia/imag...fm?imageID=1352

[Guest_Sunspot_*]

Is this a shot of Tethys? The caption says the camera was pointed towards "sky" unfortunately.

http://saturn1.jpl.nasa.gov/multimedia/ima...eiImageID=31678

I know Tethys has one huge impact crater "Odysseus"..... The crater in the image looks very unusual, there appears to be another crater in the centre.

[Decepticon]

Is this a shot of Tethys? The caption says the camera was pointed towards "sky" unfortunately.

http://saturn1.jpl.nasa.gov/multimedia/ima...eiImageID=31678

I know Tethys has one huge impact crater "Odysseus"..... The crater in the image looks very unusual, there appears to be another crater in the centre.

I think your just seeing the inner part of the crater. I admit it does look like it.

Look at the tethys map here...

http://astrogeology.usgs.gov/Projects/Satu...Tethys_full.jpg

[alan]

Sorry, I forgot to label my last post. It is Mimas.

[alan]

Is this a shot of Tethys?  The caption says the camera was pointed towards "sky" unfortunately.

http://saturn1.jpl.nasa.gov/multimedia/ima...eiImageID=31678

I know Tethys has one huge impact crater "Odysseus".....  The crater in the image looks very unusual, there appears to be another crater in the centre.

It looks like tethys to me. Here is a closer view of it
http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=29053

[David]

In this image of Tethys, what is the moonlet on the left, just above the rings?